June 10, 2011 -- Seeing the color red makes muscles move faster and with more force, a new study suggests. The finding could have important implications in sports and other activities where a quick burst of energy is needed.

"Red enhances our physical reactions because it is seen as a danger cue," researcher Andrew Elliot, professor of psychology at the University of Rochester, says in a news release.

Researchers say most people are unaware of the intensifying effect the color red has on their physical performance.

But that quick burst of energy may come at an emotional cost. The perception of threat that the color red brings also evokes worry, distraction, and self-preoccupation, which could hamper performance, say researchers.

Color Red Affects Performance

The study, published in Emotion, compared students' muscle reactions in two different experiments. In the first, a group of 30 students in fourth through 10th grade pinched and held open a metal clasp after reading their participant number written in either red or gray crayon.

In the second experiment, a group of 46 undergraduates squeezed a handgrip with their dominant hand as hard as they could while reading the word "squeeze" on a computer screen on a red, blue, or gray background.

All of the colors were matched in terms of intensity, brightness, and hue.

The results showed that in both scenarios, seeing the color red intensified the force of the participant's grip. In the second experiment, the color red also quickened the participant's reaction speed.

Researchers say previous studies have shown that seeing the color red can be counterproductive for skilled motor and mental tasks. For example, athletes competing against an opponent wearing red are more likely to lose, and students who see the color red before a test perform worse.

"Color affects us in many ways depending on the context," Elliot says. "Those color effects fly under our awareness radar."